JPWO2006090448A1 - Method for producing transparent conductive laminate and touch panel - Google Patents

Abstract

A transparent conductive laminate excellent in transparency using a film substrate and scratch resistance of a conductive thin film, and also excellent in dot characteristics as a touch panel, and this transparent conductive laminate is used for at least one electrode Provided touch panel. By forming a transparent conductive film on a specific transparent film under a temperature condition of at least 160 ° C., a transparent conductive laminate having excellent scratch resistance and hitting characteristics and excellent productivity is provided.

Description

  The present invention relates to a method for producing a transparent conductive laminate in which a transparent conductive thin film is provided on a film substrate. More specifically, the present invention relates to a method for producing a transparent conductive laminate in which a transparent conductive film is formed on a transparent film under specific conditions.

  A transparent thin film that is transparent in the visible light region and is used for purposes such as preventing static charges and blocking electromagnetic waves in transparent devices in addition to transparent electrodes in liquid crystal displays, electroluminescence displays, plasma displays, and touch panels. Has been. Conventionally, such a transparent conductive thin film is known in which an indium oxide thin film is formed on glass. However, since the base material is glass, it is inferior in flexibility and workability and heavy. It was not preferable because it was easy to break. For this reason, in recent years, in addition to flexibility and workability, it has excellent impact resistance and light weight, so transparent conductive materials based on various plastic films such as polyethylene terephthalate, polyethersulfone, polycarbonate, norbornene resin, etc. Thin films have been used.

  The conventional transparent conductive thin film manufactured using such a film base material has inferior friction resistance, and has a problem in that it is damaged during use, resulting in increased electrical resistance or disconnection. In particular, in conductive thin films for touch panels, a pair of thin films facing each other via a spacer come into strong contact with each other at the pressing point from the side of one of the substrates, so that good durability can be resisted. Although it is desired to have a characteristic, that is, a hitting point characteristic, the conventional transparent conductive thin film is inferior to such a characteristic and has a problem that the life of the touch panel is shortened.

  In order to solve this problem, Japanese Patent No. 2667680 discloses that a transparent thin film base material having a specific thickness is formed with a conductive thin film on one side in advance by sputtering or the like, and then has a specific characteristic on the other side. There has been proposed a transparent conductive laminate in which a transparent substrate is bonded through a transparent pressure-sensitive adhesive. In this method, the pressure-sensitive adhesive acts as a cushion, and the abrasion resistance of the transparent conductive thin film can be greatly improved, but the durability inherently due to insufficient adhesion between the film and the transparent conductive film. Insufficient deficiency has not been solved, and there have been problems such as a decrease in transparency due to bonding with the film and an increase in work processes.

  The present invention has been made in view of the above-mentioned problems, and is a transparent conductive laminate that improves the scratch resistance and the hit point characteristics of a transparent conductive thin film formed on a film substrate and is excellent in productivity. The object is to provide a manufacturing method.

  The method for producing a transparent conductive laminate of the present invention is characterized in that a transparent conductive film is formed on a transparent film while maintaining the temperature of the film at 160 ° C. or higher. According to this method, a transparent conductive laminate excellent in scratch resistance and hitting point characteristics can be produced with high productivity.

  According to the present invention, by forming a transparent conductive film on a transparent film under a temperature condition of at least 160 ° C., a transparent conductive laminate excellent in scratch resistance and spot characteristics can be produced with high productivity. .

  As the film substrate used in the present invention, various plastic films having transparency and having no quality change such as deformation and discoloration of the substrate in a transparent conductive film forming process at a temperature of 160 ° C. or higher. Can be used. Specific examples include polyimide, polyethersulfone, polyetheretherketone, polycarbonate, polyamide, polyacryl, acetylcellulose, polyarylate, polysulfone, and norbornene resin.

  When used for transparent electrodes of displays such as liquid crystal displays and touch panels, film bases from various viewpoints such as optical properties such as transparency and non-rotatory properties, physical properties such as low water absorption, heat resistance, mechanical strength, and price However, from the comprehensive viewpoint, polycarbonate, polyether sulfone, and norbornene resin are preferable. In recent years, quality of image quality and dimensional stability at high temperature and high humidity have become important. From this viewpoint, transparency, light dispersibility (refractive index and wavelength dependence of birefringence), and non-optical rotation Particularly preferred are norbornene-based resins having optical properties such as heat resistance and low water absorption that are far superior to other polymers.

  The norbornene-based resin includes a polymer obtained by ring-opening polymerization or addition polymerization of a monomer having a norbornene structure and another polymerizable monomer added as necessary. A cyclic olefin addition copolymer containing at least one repeating unit derived from a cyclic olefin represented by the following formula (1) is preferred.

Wherein ^(1), A 1 ~A ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, a halogenated hydrocarbon group, an ester group, It is a substituent selected from an alkoxy group, a trialkylsilyl group, a hydrolyzable silyl group, and a substituent containing an oxetanyl group, and these substituents further have an alkylene group having 1 to 10 carbon atoms or a carbon number containing an oxygen atom. It may be linked via 1-10 linking groups. A ¹ and A ² or A ¹ and A ⁴ may be bonded to each other to form an alkylene group, an arylene group, an acid anhydride, or a lactone. m is 0 or 1. ]
The cyclic olefin addition polymer optionally contains a repeating unit of a substituted cyclic olefin having an alkyl group, thereby improving the molding processability such as controlling the glass transition temperature of the obtained cyclic olefin polymer, and the resulting film Flexibility can be imparted to the substrate.

  In addition, when the cyclic olefin-based addition polymer includes a repeating unit having a hydrolyzable silyl group or oxetanyl group-containing substituent, a compound that generates an acid by heating or light irradiation (hereinafter referred to as “thermal acid generator”, respectively). ”And“ photo acid generator ”) to form a cross-linked structure and improve the chemical resistance or mechanical strength of the obtained film substrate. Here, the hydrolyzable silyl group forms a siloxane bond through a hydrolysis / condensation reaction with an acid catalyst and water or water vapor supplied as appropriate, thereby enabling cross-linking between the silyl groups. It is represented by the following formula (2) or the following formula (3).

[In the formula (2), at least one of R ¹ , R ² and R ³ represents a substituent selected from an alkoxy group, an allyloxy group and a halogen atom, and the others are alkyl groups having 1 to 3 carbon atoms. is there. ]

[In the formula (3), R ⁴ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Y represents a hydrocarbon residue of an aliphatic diol, alicyclic diol or aromatic diol having 2 to 20 carbon atoms. Show. ]
The ratio of such crosslinkable repeating units in all repeating units is usually 30 mol% or less, preferably 20 mol%, more preferably 15 mol% or less. If it exceeds 30 mol%, the water absorption of the film substrate may increase, or the shrinkage during crosslinking may be large, which may be inappropriate for the intended use.

  As the thermal acid generator, a compound capable of generating an acid at 50 ° C. or higher is preferably used, and as the photoacid generator, g-line, h-line, i-line, ultraviolet ray, far-ultraviolet ray, X-ray, electron A compound that generates a Bronsted acid or a Lewis acid by irradiation with light such as a line is used. These may be appropriately selected from known substances and may be used alone or in combination of two or more. The thermal acid generator and the photoacid generator can be used in the range of 0.001 to 10 parts by weight, preferably 0.01 to 5.0 parts by weight, per 100 parts by weight of the cyclic olefin addition polymer. When the amount is less than 0.001 part by weight, the effect of crosslinking is not sufficiently obtained, and when the amount exceeds 10 parts by weight, the mechanical strength, electrical properties, and transparency of the film substrate may be impaired.

Monomers used for obtaining these cyclic olefin addition polymers are those having an unsaturated bond not involved in polymerization, such as tricyclo [5.2.1.0 ^2,6 ] deca-3,8-diene ( When dicyclopentadiene) or ethylidene norbornene is used, the film base material is susceptible to deterioration at high temperatures. Such a problem can be avoided by hydrogenating 90 mol% or more, preferably 95 mol% or more, more preferably 99 mol% or more of the unsaturated bonds after addition polymerization of these cyclic olefins. The hydrogenation reaction can be carried out using a known heterogeneous catalyst or a homogeneous catalyst as appropriate, usually in a hydrogen pressure range of 1.0 to 15 MPa and a temperature range of 50 to 250 ° C.

The glass transition temperature of the resin constituting these film base materials is at least 180 ° C or higher, preferably 200 ° C or higher, more preferably 230 ° C or higher, and particularly preferably 250 to 400 ° C. When the glass transition temperature is 180 ° C. or lower, the film base material may be unpractical due to deformation, shrinkage, etc., when forming a transparent conductive film.
Further, the film substrate of the present invention preferably has a retardation of 15 nm or less and a total light transmittance of 90% or more at a film thickness of 100 μm. When the retardation is 15 nm or more, it becomes difficult to use the inner-type touch panel using a circularly polarizing film as an upper substrate. In addition, when the total light transmittance is less than 90%, the panel screen becomes dark.

  Also, in the film, if necessary, additives such as antioxidants, mold release agents, ultraviolet absorbers, lubricants, colorants, etc. that are usually mixed in the film, further aids for crosslinking reaction, etc. Can also be added for various purposes. The method for producing the film substrate is not particularly limited, and known melt extrusion methods, solution casting methods, coating methods, and the like can be used. From the viewpoint of the surface smoothness of the film, the solution casting method A film substrate manufactured by a coating method is preferred. Moreover, a crosslinking reaction can also be performed by heat, light, water vapor or the like in the film production process as necessary.

In the present invention, the thickness of the film substrate is preferably about 2 to 400 μm. If the thickness is less than 2 μm, the mechanical strength of the substrate itself is insufficient, and it is difficult to perform continuous operations such as applying a pressure-sensitive adhesive layer in the form of a roll or performing a hard coating process described later. From such a viewpoint, the thickness is preferably 10 μm or more, and particularly preferably 20 μm or more. When it is 400 μm or more, when it is formed into a roll, it will be curled and not only continuous work will be difficult, but it will be unusable because it remains. From such a viewpoint, the preferable thickness is 300 μm or less, and particularly preferably 250 μm or less.

  This film base material is subjected to etching treatment and undercoating treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation on the surface in advance, and a conductive thin film or adhesive provided on the surface, Or in order to make it functional as needed, the adhesiveness of the various coating agents and thin films which are formed in the film surface can also be improved. In addition, before providing the conductive thin film or the like, dust can be removed and cleaned by cleaning with a solvent, water, acid, alkali, or the like, or ultrasonic cleaning, if necessary.

  The film base material used in the present invention can be used by bonding the film base materials to each other or different film base materials with a pressure-sensitive adhesive and an adhesive. This bonding can be carried out by providing a pressure-sensitive adhesive layer or an adhesive layer on one side of the transparent film substrate and bonding the other film substrate to this. This bonding can be carried out by appropriately selecting a known method, but it is advantageous in terms of productivity to perform the film continuously in a roll shape. The pressure-sensitive adhesive layer and the adhesive layer are not particularly limited as long as they have transparency.

  In order to form the transparent conductive laminate of the present invention, a transparent conductive thin film is formed on one outer surface of the film substrate. As a method for forming a conductive thin film, any of the conventionally known techniques such as vacuum deposition, sputtering, and ion plating can be used. From the viewpoint of film uniformity and thin film adhesion to a transparent substrate. The thin film formation by sputtering is preferred. Further, the thin film material to be used is not particularly limited. For example, in addition to metal oxides such as indium oxide containing tin oxide and tin oxide containing antimony, gold, silver, platinum, palladium, copper, aluminum, Nickel, chromium, titanium, cobalt, tin, or alloys thereof are preferably used. The thickness of the conductive thin film needs to be 30 mm or more, and if it is thinner than this, it is difficult to form a continuous film having good conductivity with a surface resistance of 1000 Ω / □ or less. On the other hand, if it is too thick, it causes a decrease in transparency and the like, and a suitable thickness is about 50 to 2000 mm.

  In the present invention, it is important to control the temperature at which the transparent conductive film is formed. Conventionally, sputtering on a film has been performed at a temperature of 100 ° C. or lower. Sputtering temperature greatly affects the adhesion between the film substrate and the transparent conductive film. When a film is formed at a temperature of 160 ° C. or higher, a transparent conductive laminate excellent in durability can be obtained. In order to further reduce the resistance value, film formation at 180 ° C. or higher is further preferable, and film formation at 200 ° C. or higher is particularly preferable.

When a transparent dielectric thin film is formed on the conductive thin film thus formed, the transparency, scratch resistance, and dot characteristics are further improved, and a more preferable transparent conductive laminate is obtained. The dielectric thin film should have a refractive index smaller than that of the conductive thin film, usually 1.3 to 2.0, preferably 1.3 to 1.6. For example, CaF ₂ , MgF ₂ , NaAlF ₆ , Al ₂ O ₃ , SiOx (x = 1 to 2), ThF _{4 and the} like are preferable, and among these, SiOx is most preferable. These materials may be used in combination of two or more according to the purpose. The film thickness of the dielectric is preferably 100 mm or more, usually 100 to 3000 mm, preferably 200 to 1500 mm. If it is thin, it is difficult to obtain a continuous film, and the effect of improving transparency and scratch resistance is small. If it is thick, conductivity and transparency are deteriorated and cracks are likely to occur. The dielectric can be formed by a known method such as a vacuum deposition method, a sputtering method, an ion plating method, or a coating method.

Next, there are cases where various functions are imparted to the transparent conductive laminate depending on the purpose, but these are often more preferred embodiments. This will be described below.
The film base is easily damaged during the formation of the transparent conductive thin film and the subsequent processing or device assembly, and in the laminate, the surface opposite to the surface on which the conductive thin film is formed is bare, Surface scratches are likely to occur during use, and this causes a problem that the visibility as a transparent conductive film laminate is lowered. In order to avoid this, it is preferable to use a film substrate subjected to a hard coat treatment.

  The hard coat treatment can be performed on both sides or one side of the film before or after the transparent conductive film is formed. It is particularly preferable that the hard coat treatment is performed on the outer surface on the opposite side of the conductive thin film in the laminate. The hard coat treatment layer is preferably a cured film made of a curable resin such as melanin resin, urethane resin, alkyd resin, acrylic resin, or silicon resin. Among the hard coat treatment layers, the acrylic resin is most preferably used because it may improve the adhesion of the conductive thin film and has an effect as a base agent before forming the conductive film.

  In forming such a cured film, a composition obtained by adding various additives such as an antistatic agent and a polymerization initiator to the above-mentioned curable resin as necessary is usually diluted with a solvent to obtain a solid content. It is prepared to 20 to 80% by weight, and this is applied to one side of a transparent film substrate by means of a general solution coating means such as a gravure coater, reverse coater, spray coater, slot orifice coater or screen printing. Then, after coating so that the thickness after drying and curing is about 1 to 15 μm, it can be cured by ultraviolet irradiation, electron beam irradiation or heating after heating and drying. Prior to the formation of the hard coat treatment layer, the adhesion surface between the transparent film and the hard coat treatment layer is subjected to easy adhesion treatment such as corona discharge, ultraviolet irradiation, plasma treatment, sputter etching treatment, primer treatment, etc. Can be increased.

In addition, since the surface opposite to the surface on which the transparent conductive film is formed in the transparent conductive laminate is bare, if the surface feels dazzling or has scratches on the surface, the transparent conductive There was a problem that visibility was poor in a product using a thin film. In order to solve this problem, an antiglare treatment agent coated on the outer surface of the film is preferably used.
The antiglare treatment agent is preferably a cured film obtained by dispersing and binding silica particles to the hard coat agent described above. The silica particles used here are amorphous and porous, and a typical example is silica gel. The average particle diameter is usually 30 μm or less, preferably about 2 to 15 μm, and the blending ratio is preferably such that the silica particles are 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin. When the amount of the silica particles is small, the antiglare effect is inferior, and when the amount is large, the light transmittance and the coating strength are lowered. The antiglare treatment agent can be applied to a film and cured in exactly the same manner as the hard coat treatment described above. The antiglare treatment agent also serves as a hard coat treatment and provides not only an antiglare effect but also a scratch prevention effect.

  Next, the transparent conductive laminate provided with the antireflection layer will be described. The transparent conductive thin film is used in a display device, and when light is reflected on the surface, the image becomes unclear, and in some cases, the image is difficult to see. A transparent conductive laminate having a high light transmittance, excellent scratch resistance on the surface of the base material, and having an antireflection function capable of preventing light reflection on the surface of the base material. It is.

The antireflection layer is formed on the outer surface where the conductive thin film is not formed after the conductive thin film is formed. This antireflection layer includes a single layer structure having a refractive index different from that of the film substrate or a multilayer structure of two or more layers. In the single layer structure, a material having a smaller refractive index than that of the film substrate is selected. In order to improve the antireflection effect, when a multilayer structure is used, a material layer having a larger refractive index than that of the film substrate may be provided, and a material layer having a smaller refractive index may be provided thereon. Preferably, a material structure having a different refractive index between adjacent layers is used, but more preferably a material structure in which the refractive index of the outermost layer is smaller than the refractive index of the lower layer adjacent thereto as a multilayer structure of three or more layers. It is good to do. As a material for constitution of the antireflection layer, for example _{CaF 2, MgF 2, NaAlF 4} , Al 2 O 3, SiOx (x = 1~2), ThF 4, ZrO 2, Sb 2 O 3, Derivatives such as Nd ₂ O ₃ , SnO ₂ , TiO ₂ , and In ₂ O ₃ are listed. The refractive index is appropriately selected so as to satisfy the above relationship. This antireflection layer can be formed by a thin film forming technique similar to that of the conductive layer. The thickness is selected within a range in which the total thickness of the antireflection layer is generally about 500 to 5000 mm. Since this layer also increases the hardness of the surface, the scratch resistance is also improved.

  In addition, since this transparent conductive laminate is used in a display device, fingerprints and dirt are generated on the surface during processing and use, and there may be a problem in visibility as a whole thin film product such as feeling glare. there were. In order to solve this problem, a transparent conductive laminate having a water-repellent and antifouling treatment layer on the outer surface of the laminate is preferred depending on the application. The water repellent and antifouling treatment layer can be formed on the outer surface of the film in exactly the same manner as the hard coat formation. As a material for forming such a water-repellent and antifouling treatment layer, for example, a silicon-containing compound comprising a combination of a dimethylpolysiloxane containing a hydroxyl group or a vinyl group and a methylhydropolysiloxane, polytetrafluoroethylene, In addition to fluorine-based resins such as polychlorotrifluoroethylene, molybdenum sulfide is used alone or as a compound. In order to improve the adhesion and hardness of the treatment layer, it may be dispersed and bonded to a curable resin such as the hard coat agent described above and provided as a cured film layer on the substrate surface. Moreover, the said silica particle can also be disperse | distributed for the purpose of improving an anti-glare effect and abrasion resistance. The formation of the water-repellent and antifouling layer is not particularly limited, and a coating method, a spray method, a vacuum deposition method, a sputtering method, an ion plating method, a baking method, or the like can be used depending on the material used. Although the thickness of a process layer is not specifically limited, About 100 to 50 micrometers is good normally. If it is thin, it is difficult to obtain a continuous film and the water-repellent effect is poor. If it is thick, cracks are likely to occur.

The above-mentioned functionalization treatment can also be carried out in combination of two or more, and it is particularly efficient when used in combination with a hard coat agent, an antiglare treatment, and a water repellent or antifouling treatment agent.
[Example]
Hereinafter, the present invention will be described more specifically with reference to examples.

<Synthesis of norbornene resin, production of film base>
Bicyclo as monomers [2.2.1] hept-2-ene 700 mmol, endo- tricyclo [5,2,1,0 ^2,6] dec-8-ene (endo / exo = 96/4 ) 570 mmol, 5-triethoxysilylbicyclo [2.2.1] hept-2-ene 30 mmol, 1-hexene 5 mmol, cyclohexane 400 g as solvent, 100 g methylene chloride in a 2 L stainless steel reactor with nitrogen Prepared below.

A hexane solution of nickel octoate and hexafluoroantimonic acid are reacted at −10 ° C. and a molar ratio of 1: 1, and by-product precipitation of bis (hexafluoroantimonic acid) nickel and [Ni (SbF ₆ ) ₂ ] is filtered. Removed and diluted with toluene. The resulting hexafluoroantimonic acid modified form of nickel octoate is 0.40 mmol as a nickel atom, boron trifluoride ethyl etherate 1.2 mmol, methylalumoxane 8.0 mmol, 1,5-cyclooctadiene 0 0.4 mmol, methyltriethoxysilane 8.0 mmol, methyltriethoxysilane, 1,5-cyclooctadiene, methylalumoxane, boron trifluoride ethyl etherate, hexafluoroantimonic acid modified nickel octanoate In order, the polymerization was started. Polymerization was performed at 30 ° C. for 3 hours, and methanol was added to terminate the polymerization. The conversion ratio of the monomer to the copolymer was 92%.

  The copolymer solution was diluted by adding 480 g of cyclohexane, 660 ml of water and 48 mmol of lactic acid were added thereto, and the mixture was sufficiently stirred and mixed. Then, the copolymer solution and the aqueous phase were allowed to stand and be separated. The aqueous phase containing the reaction product of the catalyst component was removed, and the copolymer solution was put into 4 L of isopropyl alcohol to solidify the copolymer, thereby removing unreacted monomers and catalyst residues. The coagulated copolymer was dried to obtain 75 g of a cyclic olefin addition polymer A (hereinafter also referred to as “copolymer A”).

The ratio of the repeating unit derived from 5-triethoxysilylbicyclo [2.2.1] hept-2-ene in the copolymer A is 2.1 mol%, and endo-tricyclo [5,2,1,0 ^{2]. , 6} ] The proportion of repeating units derived from deca-8-ene was 35 mol%. Further, the polystyrene-equivalent number average molecular weight of the copolymer was 89,000, the weight average molecular weight was 187,000, and Mw / Mn was 2.1.

  Next, 10 g of copolymer A is dissolved in 35.5 g of cyclohexane, and pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is used as an antioxidant as a copolymer. 1.0 part per 100 parts and 0.5 part tributyl phosphite as a crosslinking catalyst were added to 100 parts copolymer. The copolymer solution was cast, and the resulting film was dried at 150 ° C. for 2 hours and further dried at 200 ° C. for 1 hour under vacuum. Further, this film was heat-treated under steam at 150 ° C. for 4 hours. Then, it dried at 200 degreeC under vacuum for 1 hour, and produced the crosslinked film A with a thickness of 100 micrometers.

The properties of the obtained film A were total light transmittance: 91%, glass transition temperature: 375 ° C., and retardation: 5 nm.
<Creation of transparent conductive laminate>
An indium-tin oxide (ITO) film was formed on a sheet having a length of 200 mm, a width of 200 mm and a thickness of 100 μm obtained by the same operation as described above using a sputtering machine under the following conditions.

Substrate temperature: 200 ° C
Target: Alloy of In ₂ O ₃ / SnO ₂ = 90/10 (weight ratio) Atmosphere: Under argon gas flow Sputter speed: 80mm / min
Sputtering pressure: 10 ^-3 torr
The average resistance value, transmittance, scratch resistance, and spot characteristics of this conductive thin film were measured and shown in Table-1.

Using the same film A as in Example 1 as the film base, ITO film formation was carried out in the same manner as in Example 1 except that the substrate temperature was changed to 250 ° C.
The average resistance value, transmittance, scratch resistance, and spot characteristics of this conductive thin film were measured and shown in Table-1.

A Teijin Pure Ace (R) WR (aromatic polycarbonate) film having a thickness of 100 μm was used as the film substrate. The characteristics of this film were total light transmittance: 90%, glass transition temperature: 210 ° C., and retardation: 20 nm. Using this film, ITO film formation was carried out in the same manner as in Example 1 except that the substrate temperature was changed to 180 ° C.
The average resistance value, transmittance, scratch resistance, and spot characteristics of this conductive thin film were measured and shown in Table-1.

  A 2 L stainless steel reactor sufficiently purged with nitrogen was charged with 750 g of dehydrated toluene and 200 g of cyclohexane, and 150 g, 75 wt% of 5-butylbicyclo [2.2.1] hept-2-ene was added. 2.2.1] 170 g of a toluene solution of hepta-2-ene was added. Ethylene was introduced until the partial pressure at 20 ° C. reached 0.015 MPa, and then the reactor valve was closed and the temperature was raised to 75 ° C. Subsequently, 1.1 ml of a 0.005 mol / l palladium acetate toluene solution, 2.75 ml of a 0.002 mol / l tricyclohexylphosphine toluene solution, and 0.001 mol / l triphenylcarbenium tetrakis (pentafluorophenyl). ) 5.5 ml of a borate solution in toluene was added to initiate polymerization. When 60 minutes and 90 minutes had elapsed after the start of polymerization, 15 g of each of the above toluene solutions of bicyclo [2.2.1] hept-2-ene was added, and the polymerization was continued for a total of 4 hours. The conversion ratio of all monomers to the polymer was 99%. The obtained copolymer solution is poured into about 10 L of isopropyl alcohol to solidify, and dried under vacuum at 80 ° C. for 17 hours to obtain a cyclic olefin copolymer B (hereinafter also referred to as “copolymer B”). It was. In copolymer B, the proportion of repeating units derived from 5-butylbicyclo [2.2.1] hept-2-ene was 39 mol%, the number average molecular weight was 42,000, and the weight average molecular weight was 175,000. .

  100 parts by weight of copolymer B was dissolved in a mixed solution consisting of 280 parts by weight of toluene and 70 parts by weight of cyclohexane, and pentaerythrityltetrakis [3- (3,5-di-t-butyl-4-hydroxy) was used as an antioxidant. Phenyl) propionate] and tris (2,4-di-t-butylphenyl) phosphite were each added in an amount of 0.6 parts by weight. The obtained copolymer solution was filtered through a membrane filter having a pore size of 10 μm, cast at 25 ° C., and the resulting film was dried at 160 ° C. for 2 hours to prepare a film B having a thickness of 100 μm. As for the characteristics of the obtained film B, the total light transmittance was 93%, the glass transition temperature was 345 ° C., and the retardation was 5 nm.

  Using the obtained film B, ITO film formation was carried out in the same manner as in Example 2. The average resistance value, transmittance, scratch resistance, and spot characteristics of this conductive thin film were measured and shown in Table-1.

Comparative Example 1

As the film substrate, a JSR ARTON (R) (norbornene-based) film having a thickness of 100 μm was used. The characteristics of this film were total light transmittance: 90%, glass transition temperature: 170 ° C., and retardation: 3 nm. Using this film, ITO film formation was carried out in the same manner as in Example 1 except that the substrate temperature was changed to 130 ° C.
The average resistance value, transmittance, scratch resistance, and spot characteristics of this conductive thin film were measured and shown in Table-1.

Comparative Example 2

Using a polyethylene terephthalate film (hereinafter referred to as PET film) having a thickness of 25 μm as a film base material, ITO film formation was carried out in the same manner as in Example 1 except that the substrate temperature was changed to 50 ° C. Then, on the other surface of the PET film, an acrylic transparent pressure-sensitive adhesive layer (polymerization ratio of butyl acrylate, acrylic acid and vinyl acetate) having an elastic modulus of 1.2 × 10 6 dyn / cm ² was adjusted. 100 parts by weight of a 100: 2: 5 copolymer was blended with 1 part by weight of an isocyanate-based crosslinking agent) to a thickness of about 20 μm, and a PET film with a thickness of 100 μm was laminated thereon. . The average resistance value, transmittance, scratch resistance, and spot characteristics of this conductive thin film were measured and shown in Table-1.

The characteristics of the film substrate were carried out as follows.
Total light transmittance: Measured with a film having a thickness of 100 μm based on ASTM-D1003.
Glass transition temperature: The glass transition temperature of the film substrate was measured at the peak temperature of tan δ (ratio of storage elastic modulus E ′ and loss elastic modulus E ″) of dynamic viscoelasticity. For measurement of dynamic viscoelasticity, use Leo Vibron DDV-01FP (Orientec), measurement frequency is 10Hz, heating rate is 4 ° C / min, vibration mode is single waveform, vibration amplitude is 2.5μm The peak temperature of the temperature dispersion of tan δ obtained by use was obtained.

Retardation: By measuring the phase difference Δ of the elliptical deflection by the elliptical deflection analysis method using a rotation analyzer type automatic ellipsometer (manufactured by Mizoji Optical Co., Ltd.), the retardation is obtained from the following formula (1). Re was calculated. In addition, the incident light angle of the laser beam was set to 0 °, and retardation was evaluated.
_{Δ = -k 0 (n x -n} y) d = -k 0 Re (1)
However, k ₀ is the wave number (= 2π / λ), n x, n y, n z is the coordinate system x, each refractive index at the time of taking y, and z orthogonal three-dimensional refractive index of the film, d is film The optical path length.

The measuring method of the characteristic of the produced transparent conductive laminated body is as follows.
-Average resistance value: Using the four probe method, nine points were measured at equal intervals, and the average value was calculated.
-Transmittance-The transmittance of light at a wavelength of 550 nm was determined using a spectral transmittance meter.
・ Abrasion resistance ・ ・ A resistance value (Rs) was measured after rubbing the surface of a thin film with a gauze with a load of 90 g / cm ² and a scratch rate of 30 cm / min and a scratch count of 100 using a Haydon surface property measuring instrument. The rate of change with respect to the initial value (Ro) was obtained.
-Dot characteristics-Two transparent conductive laminated films are placed facing each other so that the conductive thin films face each other with a spacer of 100 µm in thickness, and a rod (key tip 7R) made of urethane rubber with a hardness of 40 degrees is used. Then, after performing center hitting of 1 million times with a load of 90 g, the resistance value (Rd) was measured to determine the rate of change with respect to the initial resistance value (Ro).

As is clear from the above results, in the present invention, the transparent conductive laminate is formed by sputtering the conductive thin film while keeping the film substrate at a temperature of 160 ° C. or higher. Since the strength is increased, a transparent conductive laminate having excellent scratch resistance and hit point characteristics can be obtained.
In particular, when a conductive thin film is formed by sputtering at 230 ° C. or higher, preferably 250 ° C. or higher, using a norbornene-based resin as a film substrate, a transparent conductive laminate having excellent scratch resistance can be obtained.

Claims (8)

  A method for producing a transparent conductive laminate, comprising forming a transparent conductive film on a transparent film while maintaining the temperature of the film at 160 ° C or higher.   The manufacturing method of Claim 1 which forms the transparent conductive film, keeping the temperature of a film at 200 degreeC or more.   The manufacturing method according to claim 1, wherein the transparent film is made of a substantially amorphous polymer having a glass transition temperature of 180 ° C or higher.   The production method according to claim 1, wherein the transparent film is made of a substantially amorphous polymer having a glass transition temperature of 200 ° C. or higher.   The production method according to claim 1, wherein the transparent film has a retardation of 15 nm or less at a film thickness of 100 μm and a total light transmittance of 90% or more. The production method according to any one of claims 1 to 5, wherein the transparent film comprises a composition containing a polymer containing at least one repeating unit represented by the following formula (1);

Wherein ^(1), A 1 ~A ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, a halogenated hydrocarbon group, an ester group, It is a substituent selected from an alkoxy group, a trialkylsilyl group, a hydrolyzable silyl group, and a substituent containing an oxetanyl group, and these substituents further have an alkylene group having 1 to 10 carbon atoms or a carbon number containing an oxygen atom. It may be linked via 1-10 linking groups. A ¹ and A ² or A ¹ and A ⁴ may be bonded to each other to form an alkylene group, an arylene group, an acid anhydride, or a lactone. m is 0 or 1. ].   The transparent conductive laminated body obtained by the method in any one of Claims 1-6. A touch panel having the transparent conductive laminate according to claim 7 as at least one electrode.